In a manufacturing process of a semiconductor device or a liquid crystal display (LCD) including wet etching, cleaning, wet spin etching, coating, and developing, various kinds of acid tanks or chambers are utilized.
Conventionally, an acid tank used for wet etching, cleaning, coating, and developing is of an open type. An evacuating equipment is often used for evacuating the vaporized gas or acidic gas of the solvent utilized in the manufacturing process. However, the evacuating capacity cannot fulfill the need for protecting the workers. When the solvent or acidic gas has dispersed into the clean room, the health of the workers can be affected. Generally, the acid tank is used to process a batch of substrates, for example, the semiconductor wafers or the glass substrates of the LCDs. The parameters of the manufacturing process cannot be precisely controlled and wafer-to-wafer differences can be found. There are several kinds of processing chambers mostly for processing a single substrate, for example, a semiconductor wafer or an LCD glass substrate. The parameters of the manufacturing process can be precisely controlled and the wafer-to-wafer differences can be reduced. However, the production cost is adversely increased.
Referring to FIG. 1A, a processing chamber used for processing a substrate 105 includes a housing 101, a motor 102 mounted within the housing 101, a chuck 103 driven by the motor 102 for holding and rotating the substrate 105, and a nozzle 104 for dispensing the processing material 106 onto the substrate 105.
When the processing material 106 is dispensed onto the rotating substrate 105, the processing material 106 is uniformly distributed on the surface of the substrate 105 due to the centrifugal force.
The processing material 106 on the substrate 105 is continuously thrown out. The farther the distance from the center of the substrate 105 is, the greater the relative speed of the processing material 106 with respect to the air is.
In the case that the processing material 106 is a volatile material, the farther the distance from the center of the substrate 105 is, the more the vapor or gas of the processing material volatilizes in the open-type processing chamber. This causes ununiform concentration of the processing material 106 on the substrate 105, as shown in FIG. 1B. The horizontal axis denotes the distance away from the edge of the substrate 105, i.e., the position of the processing material 106 on the substrate 105, and the vertical axis denotes the concentration. The maximum concentration of the processing material occurs at the edge of the substrate 105, and the minimum concentration of the processing material occurs at the center thereof. Thus, the quality of the substrate is not uniform due to the within-wafer difference in a single wafer or LCD glass substrate.
Because the processing chamber apparatus illustrated in FIG. 1A is an open-type chamber for processing a substrate, the productivity is limited. Therefore, more processing chamber apparatuses have to be purchased so as to attain to the required productivity. Due to the restriction of the structure, the conventional processing chamber apparatuses cannot be stacked with one another. Therefore, they can be arranged on the ground of the clean room, and this increases the production cost.
In addition, under the condition that a plurality of processing chamber apparatuses are used for mass production, the qualities of the products are not uniform, and the repeatability thereof is poor because there are different parameters (the rotation speeds and the acceleration of the motors) between these processing chamber apparatuses.
In the processing chamber apparatus shown in FIG. 1A, the motor 102 directly drives the chuck 103, as shown in FIG. 2A. Thus, the heat generated by the motor 102 is directly transferred to the chuck 103. This causes the temperature variation of the substrate 105 mounted on the chuck 103. The temperature distribution on the substrate 105 is shown in FIG. 2B. Therefore, the temperature at the center of the substrate 105 is higher than that at the external edge, and this also causes a poor uniformity of the products.